cpu.c

#include "cpu.h"
#include <stdio.h>

void cycle() {
  print_mem();
  opcode = (mem[pc] << 8u) | mem[pc+1];
  printf("mem[pc-2]: %X\n", mem[pc-2]);
  printf("mem[pc-1]: %X\n", mem[pc-1]);
  printf("mem[pc]: %X\n", mem[pc]);
  printf("mem[pc+1]: %X\n", mem[pc+1]);
  printf("opcode: %X\n", opcode);
  printf("pc: %x\n", pc);

  switch(opcode & 0xF000) {
  case 0x0000:
    switch(opcode & 0x00FF) {
    case 0x00E0:
      op_00E0();
      break;
    case 0x00EE:
      op_00EE();
      break;
    default:
      printf("in the 0x0000 switch\n");
      op_unknown();
    }
    break;
  case 0x1000:
    op_1nnn(); break;
  case 0x2000:
    op_2nnn(); break;
  case 0x3000:
    op_3xkk(); break;
  case 0x4000:
    op_4xkk(); break;
  case 0x5000:
    op_5xy0(); break;
  case 0x6000:
    op_6xkk(); break;
  case 0x7000:
    op_7xkk(); break;
  case 0x8000:
    switch(opcode & 0x000F) {
    case 0x0000:
      op_8xy0(); break;
    case 0x0001:
      op_8xy1(); break;
    case 0x0002:
      op_8xy2(); break;
    case 0x0003:
      op_8xy3(); break;
    case 0x0004:
      op_8xy4(); break;
    case 0x0005:
      op_8xy5(); break;
    case 0x0006:
      op_8xy6(); break;
    case 0x0007:
      op_8xy7(); break;
    case 0x000E:
      op_8xyE(); break;
    default:
      op_unknown();
    }
    break;
  case 0x9000:
    op_9xy0(); break;
  case 0xA000:
    op_Annn(); break;
  case 0xB000:
    op_Bnnn(); break;
  case 0xC000:
    op_Cxkk(); break;
  case 0xD000:
    op_Dxyn(); break;
  case 0xE000:
    switch(opcode & 0x00FF) {
    case 0x009E:
      op_Ex9E(); break;
    case 0x00A1:
      op_ExA1(); break;
    default:
      op_unknown();
    }
    break;
  case 0xF000:
    switch(opcode & 0x00FF) {
    case 0x0007:
      op_Fx07(); break;
    case 0x000A:
      op_Fx0A(); break;
    case 0x0015:
      op_Fx15(); break;
    case 0x0018:
      op_Fx18(); break;
    case 0x001E:
      op_Fx1E(); break;
    case 0x0029:
      op_Fx29(); break;
    case 0x0033:
      op_Fx33(); break;
    case 0x0055:
      op_Fx55(); break;
    case 0x0065:
      op_Fx65(); break;
    default:
      op_unknown();
    }
    break;
  default:
    op_unknown();
  }

  if (delay_timer > 0) { --delay_timer; }
  if (sound_timer > 0) { --sound_timer; }
}